Electronically controlled aircraft retractable landing light with manual retraction capability

ABSTRACT

An electronically controlled retractable landing light ( 100 ) for use with aircraft. A controller ( 106 ) compares the commanded position of a lighthead ( 108 ) by means of a contactless absolute position sensor ( 212 ). Operation of a brake ( 111 ), motor ( 110 ), and lamp ( 112 ) is controlled by a control unit ( 210 ). Electrical power to the brake ( 111 ), motor ( 110 ), and lamp ( 112 ) is slowly applied and removed to reduce electromagnetic emissions and extend the service life of a power stage ( 208 ), brake ( 111 ), motor ( 110 ), and lamp ( 112 ). The lighthead ( 108 ) may be manually stowed in the event of a fault.

CROSS REFERENCE

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/339635 filed Dec. 12, 2000 entitled “ElectronicallyControlled Retractable Landing Light.”

BACKGROUND OF THE INVENTION

[0002] This application is related to a copending application entitled“Efficient Solid State Switching and Control System for RetractableAircraft Landing Lights,” by inventors D. Melvin and S. Mubaslat(attorney docket number H0002974).

[0003] 1. Field of the Invention

[0004] This invention relates to aircraft retractable landing lights.Specifically, the invention is directed to an aircraft retractablelanding light having electronic position control and switching withmanual lighthead retraction capability.

[0005] 2. Description of the Related Art

[0006] Landing lights are mounted to aircraft to illuminate the areaforward of the aircraft during night operations on taxiways and runways.A “retractable landing light” is a remotely controlled, articulatinglight that can be stowed flush with the outside surface of the aircraftwhen not in use, reducing aerodynamic drag on the aircraft. Theretractable landing light's lamp is housed in a lighthead. The lightheadis in turn hingedly affixed to a housing assembly, which is mounted tothe airframe. The lighthead is extended for use and retracted to astowed position by means of an unsealed torque-amplifying transmissionmechanism driven by an electric motor. The lighthead is held in place byan electromechanical brake. When the flight crew actuates a remotecontrol to an “Extend” position, the brake is released by applyingelectrical power to the brake's coil. Electrical power is simultaneouslyapplied to the motor, causing the motor's output shaft to turn, drivingthe transmission. The lighthead then extends to a predeterminedposition, aiming the lamp to illuminate the area forward of theaircraft. Power is then removed from the motor and the brake, causingthe lighthead to stop moving. The brake re-engages, preventing themotor's output shaft from turning. The holding force of the brake isamplified by the transmission mechanism, effectively holding thelighthead in position against the force of the windstream encountered byan aircraft in flight. The motor and brake are also simultaneouslyactivated when the remote control is placed in a “Stow” position.However, power is applied to the motor so as to cause the motor's outputshaft to rotate counter to the direction used to extend the lighthead.When the lighthead is flush with the surface of the aircraft, power isagain removed simultaneously from the motor and brake, holding thelighthead in the stowed position. The lamp may be automatically switchedon by means of a limit switch after the lighthead is extended and thenswitched off when the lighthead is retracted. Alternatively, the lampmay be manually controlled by a switch in the cockpit.

[0007] Prior retractable landing lights suffer from a number ofshortcomings. In particular, prior retractable landing lights utilizeelectromechanical limit switches to detect the lighthead's position, andelectromechanical relays for control of the motor, brake, and lamp.Electromechanical switches and relays have limited operational life dueto mechanical wear. In addition, these switches and relays generateelectromagnetic interference due to arcing at their electrical contacts.Electromechanical switches also hinder the ability to change theoperational characteristics of the retractable landing light. It isdesirable to change such operational characteristics as the extensionangle of the lighthead and the switching sequence of the lamp, brake,and motor in order to meet the particular needs of various models ofaircraft.

[0008] Another drawback of electromechanical switches is that they donot lend themselves to precise position control due to the limitedresolution of actuators. Precise position control is desirable to aimthe lamp at the proper angle. If the lighthead is extended to a smallerangle than desired, the lamp will be aimed too close to the aircraft.Conversely, if the lighthead extension angle is too great, the lamp willbe aimed too far ahead of the aircraft. Both conditions result in areduction in visibility for the flight crew. Attempts to implement moreprecise mechanical position controls in prior retractable landing lightshave resulted in more complex actuators, reducing the reliability of theretractable landing light. Mechanical wearing of the actuators, combinedwith changes in setting due to vibration, also contributes to shiftingof the lamp extension angle over time, requiring regular maintenance tore-adjust the lighthead to the proper angle.

[0009] A further disadvantage of electromechanical switches and relaysis that current flow through the motor, brake and lamp is limited onlyby the capacity of the aircraft's electrical system and wiring. Thisplaces significant stress on the relay contacts, motor, brake, and lamp,causing these components to suffer reduced service life. “Soft” startingof the motor, brake, and lamp is desirable to limit electromagneticemissions and maximize the life of these components.

[0010] A retractable landing light may be installed into more than onemodel of aircraft. However, design differences between models ofaircraft usually necessitate a change in the extension angle setting ofthe lighthead so that the lamp is properly aimed for a particularaircraft. This involves a time-consuming manual adjustment ofposition-control limit switches and repeated cycling of the retractablelanding light. Means for pre-setting selectable extension angles fordifferent models of aircraft is desired in order to reduce the amount ofmaintenance work required to install the retractable landing light intotwo or more models of aircraft.

[0011] Prior retractable landing lights utilize an open gearbox. Overtime, exposure to the elements when the lighthead is extended causes aloss of gearbox lubrication. Low viscosity grease is used to counterthis loss, but at the expense of gearbox efficiency, particularly at lowtemperature extremes.

[0012] Retractable landing lights inherently have a failure mode wherebythe lighthead cannot be retracted. The aircraft cannot be dispatched inthis condition, requiring maintenance personnel to remove and replacethe retractable landing light. This can cause significant delays in thedispatch of the aircraft, particularly if the failure occurs at a remotelocation with limited maintenance capability. Although prior retractablelanding lights have included manual retraction capability, the releasemechanisms are slow and cumbersome.

[0013] Some improvements in remotely articulating aircraft lights havebeen made, such as Hamilton et al. U.S. Pat. No. 6,315,435 B1. However,Hamilton et al. teaches the use of potentiometers having wiping elementsin contact with a resistive element. Potentiometers are subject towear-out, limiting the service life of the aircraft light. Further,Hamilton does not teach how to preconfigure the operating envelope of anarticulating light for different aircraft models, since the presetpositions disclosed in Hamilton define only the operating envelopelimits for the lighthead. Changes in the operating envelope toaccommodate different aircraft models must be made by trial-and-errorupon installation of the light into the aircraft. Also, Hamilton doesnot disclose how to reduce electromagnetic emissions and extend theservice life of the motor brake and motor. In Metz et al., U.S. Pat. No.5,355,131, an aircraft landing light utilizing contactless positionsensing is taught. However, the position sensing disclosed in Metz doesnot accommodate reconfiguration of the operating envelope for differentaircraft models, necessitating trial-and-error adjustment.

[0014] There is a need to limit inrush currents and eliminate thelow-reliability relays and switches associated with retractable landinglights. There is also a need to provide a more reliable, precise, andeasily reconfigurable means of controlling the position of theretractable landing light's lighthead. There is a further need toprotect the gearbox from the elements. Finally, there is a need toprovide capability for aircraft with failed retractable landing lightsto delay repair and to dispatch with the failed light in place.

SUMMARY OF THE INVENTION

[0015] This invention is directed to an electronically controlledretractable landing light. The retractable landing light utilizescontactless absolute position sensing to detect the position of thelighthead. The retractable landing light also incorporates electroniccontrol of the brake, motor, and lamp. An improved means of manuallyretracting the lighthead allows the aircraft to be dispatched in spiteof a failure of the retractable landing light.

[0016] Specifically, the present invention includes filters to isolateelectrical noise between the retractable landing light and the aircraft.A power supply is used to convert the power supplied by the aircraft toa level compatible with the retractable landing light. A power stageutilizes solid state switches with “soft-switching” capability to limitelectrical stress on the solid-state switches when turning the brake,motor, and lamp on and off. This soft-switching capability reduceselectromagnetic emissions from the brake, motor, and lamp, and extendsthe service life of these components. A control unit monitors mode andposition command signals and lighthead position pre-sets. The controlunit actuates the brake, motor, and lamp to move the lighthead to thecommanded position, hold the lighthead in place, and turn the lamp onand off, depending on the mode selected. The control unit also providesproper, synchronized timing of the actuation of the brake, motor, andlamp to eliminate overlapping actuation of these devices for reducedelectromagnetic emissions and to minimize the generation of switchingtransients on the aircraft electrical bus.

[0017] The present invention comprises an electronically controlledretractable light, comprising: means for mounting the retractable light;an electrical motor connected with said mounting means, said motorincluding a brake; means for reducing speed and amplifying torquecoupled to said motor, said speed reducing and torque amplifying meansbeing environmentally sealed; a lighthead connected movably with saidmounting means and connected with said speed reducing and torqueamplifying means, said lighthead including at least one lamp;contactless means for monitoring absolute position of said lighthead; atleast one solid state switch, wherein said solid state switch slowlyactivates and deactivates; and a control unit communicating with saidposition monitoring means to: monitor the position of said lighthead;provide timed actuation of said brake, motor, and lamp to preventsimultaneous actuation of said brake, motor and lamp; and to stow saidlighthead or position said lighthead at a predetermined angle.

[0018] These and other features will become better understood withreference to the following description, appended claims, andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 shows the retractable landing light;

[0020]FIG. 2 is an electrical block diagram of the retractable landinglight; and

[0021]FIG. 3 is a detail of the manual retraction means.

DETAILED DESCRIPTION OF THE INVENTION

[0022] A retractable landing light 100 is shown in FIG. 1. A baseplateor mounting means 102 is a chassis and also facilitates mounting of theretractable landing light 100 into an aircraft. Power from the aircraftis converted to a level compatible with a lamp 112 by a transformer 104.A controller 106 monitors the position of a lighthead 108. Thecontroller 106 also provides “soft start” solid-state power switching ofa motor 110, a brake 111, and the lamp 112 to extend the life of themotor 110, brake 111, and lamp 112 and reduce electromagnetic emissions.In addition, the controller 106 may provide protection from faultconditions such as excessive current or over-temperature conditions, astalled motor 110, and blockages to the lighthead 108, Further, thecontroller 106 easily facilitates changes to the setpoint of thelighthead 108 and the addition of new functions. The controller 106 mayoptionally include means for regularly flashing the lamp 112 on and offor from a higher voltage to a lower voltage to attract the attention ofother aircraft operating in the vicinity, reducing the risk of runwayincursions.

[0023] An environmentally sealed gearbox or other means for reducingspeed and amplifying torque 114 converts the high-speed, low-torqueoutput of the motor 110 to a low-speed, high-torque rotationalmechanical drive. The output of gearbox 114 is coupled to means fordriving and linking, such as a pair of drive arms 116 and connectinglinks 118, which provide leverage to move the lighthead 108 against theforce of the airstream encountered by an aircraft in flight.

[0024] Vibration-damping gasketing 120 is placed between the lamp 112and a lamp retainer 122. The vibration-damping gasketing 120 equallydistributes the retaining force applied to the lamp 112 by lamp retainer122, reducing the risk of failure of lamp 112 due to cracking of theglass envelope of lamp 112. Further, the vibration-damping gasketing 120reduces mechanical stress on the filament of lamp 112 due to vibration,aiding to extend the service life of the lamp 112.

[0025] A block diagram of the electrical portion of the retractablelanding light 100 is shown in FIG. 2. A set of filters 202 and 204isolate electrical noise, such as electromagnetic interference, betweenthe aircraft and a power supply 206, a power stage 208, and a controlunit 210. The power supply 206 converts electrical power from theaircraft to a level compatible with the control unit 210 and the powerstage 208. The position of the lighthead 108 is sensed by an absoluteposition sensor 212. Means for controlling such as the control unit 210provides control functions, such as for example, turning the lamp 112 onand off, actuation of power to brake 111 and motor 110, setting thedirection of rotation of the motor 110, and resolution of the positionof the lighthead 108. The power stage 208 provides “soft start”electrical drive for the brake 111, motor 110, and the lamp 112 toreduce electrical stress on brake 111, motor 110, and lamp 112 and toreduce electromagnetic emissions from the brake 111, motor 110, and lamp112. The control unit 106 may also monitor for fault conditions, such asexcessive current or over-temperature conditions, a stalled motor 110,and blockages to the lighthead 108. If a fault is detected, control unit106 will disable power stage 208 until the fault is cleared.

[0026] The extend angle setting switch 214 is set to the desiredposition for a particular aircraft when the retractable landing light100 is installed into the aircraft. The extend angle setting switch 214provides selectable preset position commands to the control unit 210 forpositioning the lighthead 108 to one or more predetermined extensionangles, eliminating the time-consuming step of manually calibrating theextension angle of lighthead 108 for a particular aircraft. Extend anglesetting switch 214 may utilize one or more bits of digital logic, or maybe an analog voltage level, such as derived from a voltage dividernetwork. Means for monitoring the state of the extend angle settingswitch 214, such as control unit 210, is configured such that the stateof extend angle setting switch 214 represents a predetermined extensionangle for lighthead 108. Upon receiving an “Extend” command at terminal218, control unit 210 will position the lighthead 108 at the extensionangle represented by the state of extend angle setting switch 214.

[0027] Contactless means for monitoring absolute position 212, such as aHall-effect rotary position sensor, is coupled to the lighthead 108 andprovides the control unit 210 with continuous information on the angularextension position of the lighthead 108 so that the control unit 210 cancontrol actuation of the brake 111, actuation of the motor 110, thedirection of rotation of the motor 110, and illumination of the lamp 112by appropriate synchronization of the on-off control of the power stage208. Incremental-type position encoders may alternatively be used, butabsolute-type position encoders are preferred because absolute-typeposition encoders do not require periodic calibration to an indexposition.

[0028] The retractable landing light 100 is commanded to extend orretract, and to switch the lamp 112 on and off, by means of controlsignals supplied to the control unit 210. To command the lighthead 108to a stowed position when the retractable light 100 is not in use, anelectrical control signal is applied to a “Retract” input terminal 216,causing the lighthead 108 to move to a predetermined stow position,preferably out of the airstream to minimize aerodynamic drag on theaircraft. To command the lighthead 108 to extend, an electrical controlsignal is applied to an “Extend” input terminal 218. To turn on the lamp112, an electrical control signal is applied to a “Lamp On” terminal220. The control unit 210 may optionally provide means for indicating tothe flight crew that the lighthead 108 is in an extended position, suchas a status output signal via a “Extended Indicator” terminal 224. Theoutput signal present at terminal 224 is wired to an appropriateindication means in the cockpit, such as an indicator light or a cautionand warning computer. The voltage level present at the “ExtendedIndicator” terminal 224 may be fixed at a level compatible with theassociated cockpit indication means by connecting an appropriate voltagesource to an “Indicator Supply” input terminal 222.

[0029] If the lighthead 108 cannot be stowed due to a failure condition,the aircraft may not be permitted to dispatch due to operatinglimitations for the aircraft. The retractable landing light 100 mayoptionally include means for disengaging the lighthead 108 to manuallystow the lighthead 108 as shown in FIG. 3 to overcome this limitation.The manual retraction means will allow the aircraft to dispatch underconditions where the lighthead 108 must be stowed but operation of theretractable landing light 100 is not required, such as daylightoperations. To manually stow the lighthead 108, one or more releasebolts 302 are removed. This disengages the drive arms 116 from thegearbox 114, allowing the lighthead 108 to be pivoted to the stowedposition by pushing the lighthead 108 until the lighthead 108 is flushwith the baseplate 102. The release bolts are then re-installed whileholding the lighthead 108 in place, securing the lighthead 108 in thestowed position. The aircraft may then be dispatched.

[0030] In operation, the landing light 100 may be actuated by one ofmanual and automatic means. For manual operation, the flight crewcommands the desired position for the retractable landing light 100 bymeans of a control switch remotely mounted in the cockpit.Alternatively, the command signal may be generated automatically, suchas from an “air-ground” switch that senses whether or not the aircraftis in flight. When the controller 106 receives a command signal, thecontroller 106 compares the commanded position to the actual position oflighthead 108, using absolute position encoder 212. The controller 106first actuates the brake 111 and then the motor 110, which in turndrives a speed reduction and torque amplification transmission means114, such as a gearbox. The gearbox 114, which is sealed from exposureto the elements, converts the high-speed, low-torque output of the motor110 into a low-speed, high-torque mechanical drive capable of extendingthe lighthead 108 against the force of the windstream encountered by anaircraft in flight. The gearbox 114 moves a drive arm 116, attached tothe lighthead 108 by a set of connecting links 118, causing thelighthead 108 to extend or retract as needed until the proper positionfor the lighthead 108 is reached. The controller 106 controls power tothe lamp 112, switching the lamp 112 on when the lighthead 108 is in anextended position and switching the lamp 112 off when the lighthead 108is in a stowed position. The controller 106 provides a “soft start”turn-on of the lamp 112 by limiting inrush current, thereby extendingthe life of the lamp 112. The lighthead 108 further aids to increase thelife of lamp 112 through the use of vibration-damping gasketing 120 toreduce mechanical stress on the lamp 112.

What is claimed is:
 1. An electronically controlled retractable light,comprising: means for mounting the retractable light; an electricalmotor connected with said mounting means, said motor including a brake;means for reducing speed and amplifying torque coupled to said motor,said speed reducing and torque amplifying means being environmentallysealed; a lighthead connected movably with said mounting means andconnected with said speed reducing and torque amplifying means, saidlighthead including at least one lamp; contactless means for monitoringabsolute position of said lighthead; at least one solid state switch,wherein said solid state switch slowly activates and deactivates; and acontrol unit communicating with said position monitoring means to:monitor the position of said lighthead; provide timed actuation of saidbrake, motor, and lamp to prevent simultaneous actuation of said brake,motor and lamp; and to stow said lighthead or position said lighthead ata predetermined angle.
 2. The electronically controlled retractablelight of claim 1, further comprising an extend angle setting switch toset at least one extension setpoint for said lighthead.
 3. Theelectronically controlled retractable light of claim 2, furthercomprising means to monitor the state of said extend angle settingswitch.
 4. The electronically controlled retractable light of claim 1,further comprising the means for reducing speed and amplifying torqueincluding means for driving and linking, and said retractable lightfurther comprising means for disengaging said means for driving andlinking from said means for reducing speed and amplifying torque tomanually stow said lighthead.
 5. The electronically controlledretractable light of claim 1, wherein said lighthead includes a lampretainer and vibration-damping gasketing is positioned between said lampand said lamp retainer.
 6. The electronically controlled retractablelight of claim 1, wherein said control unit provides means forindicating to the crew when said lighthead is not in a stowed position.7. The electronically controlled retractable light of claim 1, whereinsaid retractable light is actuated by one of manual and automatic means.8. The electronically controlled retractable light of claim 1, furtherincluding means to regularly flash said lamp to attract attention. 9.The electronically controlled retractable light of claim 1, wherein saidcontrol unit additionally monitors for over-current faults,over-temperature faults, stall of said motor, and blockages of saidlighthead and wherein said control unit disables said solid stateswitches until said faults, motor stall, and blockages are no longerpresent.
 10. The electronically controlled retractable light of claim 1,wherein said retractable light is an aircraft light.
 11. Anelectronically controlled retractable light, comprising: means formounting the retractable light; an electrical motor connected with saidmounting means, said motor including a brake; means for reducing speedand amplifying torque coupled to said motor, said means for reducingspeed and amplifying torque being environmentally sealed, and the meansfor reducing speed and amplifying torque including means for driving andlinking, and said retractable light further comprising means fordisengaging said means for driving and linking from said means forreducing speed and amplifying torque to manually stow said lighthead; alighthead connected movably with said mounting means and connected withsaid speed reducing and torque amplifying means, said lightheadincluding at least one lamp; contactless means for monitoring absoluteposition of said lighthead; at least one solid state switch, whereinsaid solid state switch slowly activates and deactivates; an extendangle setting switch to set at least one extension setpoint for saidlighthead; and a control unit communicating with said positionmonitoring means to: monitor the position of said lighthead; monitor thestate of said extend angle setting switch; provide timed actuation ofsaid brake, motor, and lamp to prevent simultaneous actuation of saidbrake, motor and lamp; and to stow said lighthead or position saidlighthead at a predetermined angle.
 12. An electronically controlledretractable light, comprising: means for mounting the retractable light;an electrical motor connected with said mounting means, said motorincluding a brake; means for reducing speed and amplifying torquecoupled to said motor, said means for reducing speed and amplifyingtorque being environmentally sealed, and the means for reducing speedand amplifying torque including means for driving and linking, and saidretractable light further comprising means for disengaging said meansfor driving and linking from said means for reducing speed andamplifying torque to manually stow said lighthead; a lighthead connectedmovably with said mounting means and connected with said speed reducingand torque amplifying means, said lighthead including at least one lamp,a lamp retainer, and vibration-damping gasketing placed between saidlamp and said lamp retainer; contactless means for monitoring absoluteposition of said lighthead; at least one solid state switch, whereinsaid solid state switch slowly activates and deactivates; an extendangle setting switch to set at least one extension setpoint for saidlighthead; and a control unit communicating with said positionmonitoring means to: monitor the position of said lighthead; monitor thestate of said extend angle setting switch; provide timed actuation ofsaid brake, motor, and lamp to prevent simultaneous actuation of saidbrake, motor and lamp; stow said lighthead or position said lighthead ata predetermined angle; and to provide means for indicating to the crewwhen said lighthead is not in a stowed position.
 13. A process forproviding an electronically controlled, retractable light, comprising:providing means for mounting the retractable light; placing at saidmounting means an electrical motor, said motor including a brake;providing environmentally sealed means for reducing the speed andamplifying the torque of said motor; movably connecting a lighthead tosaid mounting means and connecting said lighthead with said means forspeed reducing and torque amplifying, said lighthead including at leastone lamp; supplying electrical power to said brake, motor, and lamp suchthat power to said brake, motor, and lamp can be slowly activated anddeactivated; applying torque to said lighthead by way of said means forspeed reducing and torque amplifying; providing contactless means formonitoring absolute position of said lighthead; providing means forcontrolling said lighthead in order to: monitor the position of saidlighthead; provide timed actuation of said brake, motor, and lamp toprevent simultaneous actuation of said brake, motor and lamp; andstowing said lighthead or positioning said lighthead at a predeterminedangle of extension.
 14. The process of claim 13, further comprising thestep of providing at least one extension setpoint for said lighthead.15. The process of claim 14, further comprising the step of monitoringsaid extension setpoint.
 16. The process of claim 13, further comprisingthe steps of providing said means for speed reducing and torqueamplifying with means for driving and linking, and providing means fordisengaging said means for driving and linking from said means for speedreducing and torque amplifying to manually stow said lighthead.
 17. Theprocess of claim 13, further comprising the steps of adding a lampretainer to said lighthead and placing vibration-damping gasketingbetween said lamp and said lamp retainer.
 18. The process of claim 13,further comprising the step of providing means for indicating to thecrew when said lighthead is not in a stowed position.
 19. The process ofclaim 13, further comprising the step of regularly flashing said lamp toattract attention.
 20. The process of claim 13, further comprising thestep of monitoring for over-current faults, over-temperature faults,stall of said motor, and blockages of said lighthead, and disabling saidmotor, brake, and lamp until said faults, motor stall, and blockages areno longer present.
 21. A process for providing an electronicallycontrolled, retractable light, comprising: providing means for mountingthe retractable light; placing at said mounting means an electricalmotor, said motor including a brake; providing environmentally sealedmeans for reducing the speed and amplifying the torque of said motor;movably connecting a lighthead to said mounting means and connectingsaid lighthead with said means for speed reducing and torque amplifying,said lighthead including at least one lamp; supplying electrical powerto said brake, motor, and lamp such that power to said brake, motor, andlamp can be slowly activated and deactivated; applying torque to saidlighthead by way of said means for speed reducing and torque amplifying;providing contactless means for monitoring absolute position of saidlighthead; providing means for controlling said lighthead in order to:monitor the position of said lighthead; provide timed actuation of saidbrake, motor, and lamp to prevent simultaneous actuation of said brake,motor and lamp; stowing said lighthead or positioning said lighthead ata predetermined angle of extension; providing at least one extensionsetpoint for said lighthead wherein said extension setpoints include asetting for positioning said lighthead at a stowed position; monitoringsaid extension setpoint; and providing said means for speed reducing andtorque amplifying with means for driving and linking, and providingmeans for disengaging said means for driving and linking from said meansfor speed reducing and torque amplifying to manually stow saidlighthead.
 22. A process for providing an electronically controlled,retractable light, comprising: providing means for mounting theretractable light; placing at said mounting means an electrical motor,said motor including a brake; providing environmentally sealed means forreducing the speed and amplifying the torque of said motor; movablyconnecting a lighthead to said mounting means and connecting saidlighthead with said means for speed reducing and torque amplifying, saidlighthead including at least one lamp; supplying electrical power tosaid brake, motor, and lamp such that power to said brake, motor, andlamp can be slowly activated and deactivated; applying torque to saidlighthead by way of said means for speed reducing and torque amplifying;providing contactless means for monitoring absolute position of saidlighthead; providing means for controlling said lighthead in order to:monitor the position of said lighthead; provide timed actuation of saidbrake, motor, and lamp to prevent simultaneous actuation of said brake,motor and lamp; stowing said lighthead or positioning said lighthead ata predetermined angle of extension; providing at least one extensionsetpoint for said lighthead wherein said extension setpoints include asetting for positioning said lighthead at a stowed position; monitoringsaid extension setpoint; providing said means for speed reducing andtorque amplifying with means for driving and linking, and providingmeans for disengaging said means for driving and linking from said meansfor speed reducing and torque amplifying to manually stow saidlighthead; adding a lamp retainer to said lighthead and placingvibration-damping gasketing between said lamp and said lamp retainer;and providing means for indicating to the crew when said lighthead isnot in a stowed position.